Many buildings contain egress routes which can be immersed in darkness in the event of a fire or other emergency. In such a situation, individuals cannot locate the building exits because escape routes and emergency exits are no longer visible.
It has therefore been known and is desirable to provide buildings with illumination systems which identify escape routes in the event of an emergency. There are two general classes of systems available. The first is electrically-operated systems. These normally consist of a series of emergency lights powered by an emergency generator or by batteries. The second is photoluminescent systems. These normally consist of photoluminescent products placed on the walls, floors, stairwells and/or around the door frames of escape routes.
Some drawbacks of electrical systems are their expense and the fact that they require a power source, which can fail during an emergency. Furthermore, because of their expense they are typically only used at specific points along an escape route rather than along the entire route. Moreover, they are not continuous.
Another problem with existing systems is that they are usually located high on walls or on the floor. It would be advantageous if warning systems could have a low location on the walls, since people often drop to the floor in the case of fire or the like.
Photoluminescent materials are less expensive than the aforementioned electrical products or systems; therefore, they are economical enough to be used along, and therefore illuminate, the entire escape route. Such materials are easy to install and are relatively maintenance free. These materials contain a photolurninescent component which absorbs and stores sunlight and/or artificial light. The materials become photoluminescent, i.e. they glow in darkness, thereby identifying escape routes. One problem with many photoluminescent materials is that they are applied on-site to walls or floors. This creates considerable labor expense. Furthermore, the materials can wear off or be torn loose. Examples of such materials are photoluminescent tapes, paints and other products which are applied in a secondary process.
The expense of on-site application is eliminated if the photoluminescent materials are combined with a nonluminescent product in a factory and the combined product is installed on the egress route. In this case, the photoluminescent component, usually photoluminescent tape, is applied to another product, such as a molding, floor tile, stair tread or wall panel, in a secondary combining operation. The labor required to combine the photoluminescent component with the nonluminescent product, however, still adds considerable cost because a separate manufacturing step, i.e. the application of the photoluminescent material, must be undertaken. Additionally, the photoluminescent component can still wear off or be torn loose after the product has been installed.
It has been known to make photoluminescent vinyl sheet goods and tiles utilizing the calendaring method. This eliminates the step of applying photoluminescent tapes or coatings to the products in a secondary process. The molded products disclosed in the prior art, however, are not provided, nor could they be easily manufactured, in continuous strips. Additionally, the prior art discloses only molded products which are formed entirely from photoluminescent material. Also, the prior tiles are laminated, and the photoluminescence does not extend through the tile to its back. No products comprised of an integral combination of photoluminescent and nonluminescent materials are disclosed.
U.S. Pat. No. 4,801,928 shows an egress detection system including at least three electroluminescent lamps in a linear arrangement and circuitry for sequentially illuminating the lamps. Each lamp contains two sets of indicators in the form of arrows pointing in opposite directions. The arrows pointing toward one exit are illuminated in the case of one sensed danger and the arrows pointing in the opposite direction are illuminated in response to a second sensed danger.
U.S. Pat. No. 4,401,050 discloses a continuous adhesive transparent sheet having discontinuous phosphorescent arrows or other indicia protruding therefrom. The indicia is either formed within or attached to the adhesive sheet. If the indicia is formed within the sheet, the phosphorescent material is added in a secondary combining operation.
U.S. Pat. No. 4,385,586 discloses a path-marking system employing a series of photoluminescent accessories. Each individual accessory has tactile characteristics of shape and surface contacts which, in combination, indicate direction and distance to the nearest evacuation exit.
U.S. Pat. No. 2,169,657 discloses a woven floor covering made with yarn dyed with rhodamine, a substance which fluoresces when exposed to ultraviolet light. Another embodiment discloses a woven floor covering printed with fluorescent or ultraviolet light-sensitive pigments. In another embodiment, a floor covering is painted with fluorescent paint.
U.S. Pat. No. 2,387,512 discloses a photoluminescent adhesive tape. The tape is provided with a layer of photoluminescent pigment which is protected from the atmosphere by a transparent film which does not interfere with the activation of the photoluminescent pigment on exposure to light.
The present invention improves upon the teachings of the prior art by providing a product comprised of a continuous strip of nonluminescent material coextruded with photoluminescent material to form an integral product in which the two materials are molecularly bonded.